Long-term effects of the COVID-19 pandemic on children's physical activity and sedentary behavior.

Background: During the early months of the COVID-19 pandemic, decreases in physical activity (PA) and increases in sedentary behavior (SB) were reported among children in the United States (U.S.). This follow-up analysis examines 13-month effects of the COVID-19 pandemic on children's PA and SB one year into the pandemic. Methods: Parents of 5-13-year-old children in the U.S. (N = 71) reported on their child's PA and SB during the early COVID-19 period (April-May 2020) and again 12-14 months later (June-July 2021). Results: Paired t-tests showed significant within-subject reductions in SB minutes per day (M diff = -86.20, t = 3.26, p < 0.01) but no changes in PA minutes per day. Separate mixed-model repeated-measures analysis of covariance procedures found that within-subject changes in PA and SB did not differ by child sex or age. Conclusion: As COVID-19 restrictions lessened, there were more opportunities for children to reduce SB, but there were still barriers to engage in PA.

Morning Serum Cortisol Is Uniquely Associated with Cardiometabolic Risk Independent of Body Composition in Latino Adolescents.

Background: Alterations in morning serum cortisol (MSC) have been associated with higher cardiometabolic risk. This finding has been documented primarily in populations with overweight or obesity; however, it has not been clearly established if obesity plays a requisite role in this relationship. This study seeks to extend earlier findings by examining whether body composition measures alter the relationship between MSC with glucose and insulin markers, blood pressure, and lipid parameters in Latino youth in middle adolescence. Methods: This cross-sectional study included 196 healthy adolescents (130F/66M; mean age: 16.4 ± 0.6 years; 95% Latino; mean body mass index, BMI: 24.3 ± 5.7) from Los Angeles, California. Morning cortisol, glucose, insulin, glycated hemoglobin, and lipids (triglycerides and high-density lipoprotein cholesterol) were assessed from a fasting blood sample. Sitting systolic and diastolic blood pressure was averaged from duplicate measures. Body composition measures included BMI and waist circumference, which were used as proxies for total body and abdominal adiposity, respectively. Triplicate measurements of weight and height were averaged for calculation of BMI; age- and sex-specific BMI z-score was used to classify into normal BMI or overweight/obese BMI status. Waist circumference was measured in duplicate and the average was used to classify participants into two strata: normal/healthy waist circumference (<90th percentile for age, sex, and ethnicity) and high waist circumference (≥90th percentile). Results: The primary findings were that higher MSC was associated with higher fasting glucose and systolic blood pressure after adjusting for age, sex, and BMI z-score (and/or waist circumference). BMI status or waist circumference status did not alter these relationships. Main Conclusion: Our results suggest that the relationships between hypothalamic-pituitary-adrenal axis function and certain cardiometabolic risk factors may be independent of adiposity. Future research is warranted to discover the contributors and underlying mechanisms of these relationships in adolescent populations. ClinicalTrials.gov identifier: NCT02088294.

A Systematic Review of the Associations of Adiposity and Cardiorespiratory Fitness With Arterial Structure and Function in Nonclinical Children and Adolescents.

PURPOSE: To summarize the evidence on associations of adiposity and cardiorespiratory fitness (CRF) with arterial structure and function in nonclinical children and adolescents. METHODS: Two researchers conducted a search in 5 electronic databases in April 2022 to find studies in nonclinical youth (age 5-17.9 y) reporting multivariable associations. Studies were eligible if adiposity and/or CRF were used as the predictor and arterial structure and/or function was the outcome. The Quality Assessment Tool for Quantitative Studies was used to assess methodological quality for experimental studies, and a modified version was used for observational studies. RESULTS: Ninety-nine studies (72.7% cross-sectional) were included. Ninety-four assessed associations between adiposity and arterial outcomes, most using overall body proportion (n = 71), abdominal (n = 52), or whole-body adiposity (n = 40). Most evidence was inconsistent or nonsignificant, but 59 studies suggested higher abdominal adiposity and worse body proportion were associated with adverse arterial outcomes. Twenty-one assessed associations between CRF and arterial outcomes, with findings inconsistent. Most evidence was rated weak in quality. CONCLUSION: While high adiposity may contribute to poor arterial outcomes, evidence is limited regarding CRF. Future studies should disentangle these associations by studying youth with healthy adiposity but poor CRF, or vice versa, using longitudinal or experimental study designs.